Boil wort in autoclave/pressure cooker

I was reading about cooking with pressure cookers then I asked my self the question about doing the boil in a pressure cooker or autoclave -- if you could get one big enough.
There definitely would be problems -- you wouldn't get the hot break. But when you chill your wort you would get the cold break. (Perhaps the hot break material would go out with the cool break.)

But you might save a lot on electricity and you might need minimal hopping?
YOu would get a sterile wort too.

Any ideas?

Unfortunately it isn't an acceptable method because volatiles must be boiled off during the boil. However, some breweries use low pressure boiling to boil at lower temperatures and save some energy, but they still can't go too low on the temp.

gotta boil off the DMS when mashing grains, unless you like creamed corn beer

I have done a few mason jars in the pressure cooker to seterilize for future yeast starters. You DO get hot break crap so I now pull from my BK before I add yeast.

You most definitely would get hot break - and more of it to boot! I routinely bring leftover wort into work to autoclave for starters. This stuff really likes to boil over, so I have to use a real slow exhaust cycle. If the pressure drops too fast while the temp is above 100 C it will boil over. I get a lot of break after the autoclave, and this is with already once boiled wort.

don't maltsters make extract in pressure vessels? lowers the boiling point to avoid excess carmelazation etc.

moosetav said:

don't maltsters make extract in pressure vessels? lowers the boiling point to avoid excess carmelazation etc.

Click to expand...

Vacuum boiling

I mean...you could try it yourself and find out?

Wort is sterilized by boiling it for an hour anyway, as far as I know.

And yes, cyberwolf is right, maltsters boil under a vacuum to make DME/LME, not with greater than atmospheric pressure. Greater pressure increases the boiling point so you can raise it to a higher temperature (think pressure cooker); a vacuum does the opposite, presumably so that volatiles can be lost while not caramelizing the wort.

Just for fun, I was looking up isomerization of alpha acids and how it related to temperature and I found this in a paper abstract:

Maximum solubility of alpha acids in a pH 5.2 buffered aqueous solution was 90ppm. Hop isomerization kinetics examined over a broad range of temperatures showed a rate coefficient of 0.0153(1/sec) for atmospheric boiling conditions. At 70deg C, less than 10% of alpha acids were converted in a 90 minute boil. At 120deg C, only 30 minutes were required for 90% conversion, with subsequent loss of iso-alphas to degradation products following. Activation energy was determined to be 36.375 kJ per mole.

Precise understanding of isomerization kinetics allows improved accuracy in hopping rate calculation to achieve target concentrations of bitter compounds in wort, despite varying temperatures as the kettle approaches boiling, or as wort encounters a lag time prior to entering a heat exchanger for cooling. Also, understanding of kinetics is essential if novel regimes (short duration, high temperature, pressurized boiling) are to be explored for potential energy savings.

So if you tried this for an extract brew, it seems like you could be in business for a low duration boil.